# Comsol Magnetic field data to Fluent MHD

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December 5, 2014, 22:00
Comsol Magnetic field data to Fluent MHD
#1
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Dinushke
Join Date: Aug 2013
Location: Victoria, Australia
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Hi,
Does anyone know how to exactly transfer magnetic field data to the external magnetic field option in the fluent MHD module. From what I see the external mag. field data format in the fluent mhd is quite strange (see attachment).

Thanks,
Dean
Attached Images
 Ext_fluent.JPG (33.8 KB, 67 views)

 December 17, 2018, 05:32 #2 New Member   Eduard Join Date: Dec 2018 Posts: 3 Rep Power: 7 For someone, this topic remains relevant. Can anyone explain the structure of the file that dean993 attached? What does "data point" mean in the MHD fluent manual? Last edited by eduardvinter; December 17, 2018 at 06:52.

 December 17, 2018, 08:54 #3 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,627 Rep Power: 65 You just provide a big giant list in the order given nX = number of x coordinates nY = number y coordinates nZ = number of zcoordinates X1 thru Xn, listall the x coordinates up to nX in number Y1 thru Yn, list all the y coordinates up to nY in number Z1 thru Zn, list all the z coordinates up to nZ in number nAc freq BXre means real part of Bfield in X-direction, BXim means imaginary part of Bfield in Y-direction

December 17, 2018, 09:28
#4
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Eduard
Join Date: Dec 2018
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This part of the file is clear.

I encountered a misunderstanding of the term "data point" in the manual.

Information from the Appendix C of MHD module manual:

Quote:
 The rest of the data file contains the magnetic field data points. Each line defines the components of the real and imaginary parts of the magnetic field vector on one data point. The data points are indexed as: l=i+nX((j-1)+nY(k-1)) i=1,...,nX, j=1,...,nY; k=1,...,nZ The data is listed in the ascending order from 1 to n, where n is the total number of data points given by n= nXnYnZ.
As I understood l is a line number in the array of B.

For instance, I have an alternating magnetic field calculated in ANSYS APDL. I can write APDL macro for extracting magnetic field induction from each element, but I have to extract this magnetic field induction from each data point. What is it?

Thanks

 December 17, 2018, 13:31 #5 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,627 Rep Power: 65 The meaning of external is that it comes from some black box without any meaning. You have fields at x,y,z. Just list them. It doesn't matter to the interpreter whether they come from faces/cells/nodes.